Carbureter for internal-combustion engines.



E. ll". ABERNETHY.

CARBURENTER FIOR INTERNAL COMBUSTION ENGINES.

APPLlcAloN .FILED MAR. 25. 1904.

L l 37;?27 `r Patented May 4, 1915.

2 SHEETS-SHEET l.

@9i/knew@ f am@ Z( am E. E. ABERNETHY.

CARBURETER FOR INTERNAL COIVIBUSTION ENGINES.

APPLICATION FILED MAR. 25, 1904.

2 SHEETS-SHEET 2.

Patented May 4, 1915.

awww.

I Q/@i/neozym unina snare rara entren.

EDWIN F. A BEIRNETHY, OF BROOKLYN, NEW `YORK, ASSIGNOR 0F ONE-HALF T0 GEORGE H. ABERNETHY, OF BROOKLYN, NEW YORK.

CARBURETER FOR INTERNAL-COMBUSTION ENG-INES.

Skpecication of Letters Patent.

Patented May 4l, 19315.

Application led March 2.5, 1994. Serial No. 199,917.

To all whom t may concern Be it known that I, EDWIN F. ABERNETHY, a citizen of the United States, residing at Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Carbureters for Internal-Combustion Engines, of which vthe following is a full, clear, and exact descrip- Elon.

This invention relates to improvements in carbureters for use in connection with internal combustion engines.

Engines of this class are new used under a great variety of conditions and for different classes of Work, but they may be divided generally into three classes, first, stationary engines, second, marine engines, and, third,

engines for use on motor driven vehicles,

such as automobiles. Engines of the first class are sometimes supplied with avmixture of gas and air, the gas being drawn from a supply main,.or a hydrocarbon may be vaporized and mixed With air toproduce a combustible mixture for use as a vehicle in propelling the engine.

-In the practical service of marine engines designed for the propulsion of marine vessels, it is customary to install the engine near the stern or about amidships, While the hydrocarbon tank is located at a point remote from the engine, usually in the bow of the vessel, and elevated above the engine in order to afford a liquid head and to insure a supply to the carbureter. As long as the sea, or other body of water, is comparatively calm, the carbureter Willbe supplied With hydrocarbon under gravity feed; but when the Water is rough and the Vessel pitches in descending into the troughs of the Waves, the level ofthe fuel supply falls below the carbureter and the engine, so that the fuel supply is not available on the stroke of the engine, hence the combustible mixture cannot be supplied to the engine at eachstroke of the piston thereof. Somewhat analogous conditions are encountered in the service of internal combustion engines on motor-driven vehicles when hydrocarbon under gravity is to be supplied to the carbureter, because on' the ascent of declivities or ony sidewise tilting-'bf the vehicle the fuel head is not availablej in supplying the carbureter with fuel for adinixture with air to producethe com-l bustible mixture. In the present mventlon, l seek to overcome these objections by the provision of a novel type of carbureter yvhich is so constructed and arranged as to insure at all times and under all conditions a full and ample supply of fuel for admixture with the air to produce ,the combustible mixture. l also provide a construction which secures a proportionate admixture of air and fuel under changes in the speed or load of the engine, that is to say, under slow speed the same quality or grade of the combustible mixture is supplied to the engine as under high speed or heavy load conditions. l also provide means by Which the volume of air supplied at each opening movement of the air valve may be regulated or controlled to change the quality or grade of the mixture as may be desired; such control of the air supply being secured Without stopping the engine or throwing the carbureter even temporarily out of service.

The broad feature of the present invention consists in the provision of suction operated means in the carbureter for creating a partial vacuum therein, such vacuum being available in drawing into the carburetera certain quantity of fuel which is proportionate to the supply of air. This mode of operation is important because in the absence of a fuel head under the conditions heretofore reci tedthe fuel, either liquid or gaseous, Will be sucked or drawn into the mixing chamber for admixture With the air.

Another part of my invention resides in a fuel valve controllable by the opening movement of a suction-operated air. valve, said fuel-valve being peculiarly fashioned or constructed to regulate the admission of fuel proportionately to the volume of air admitted tothe mixing chamber.

Another part of my invention resides in the employment of an adjustable air valve,

arranged to be moved endwise by a suction draft through the mixing chamber. vThis valve consists of two parts each having vair the claims hereto annexed.`

Reference is to behad to the accompanying drawings, forming a part of this specification, in which similar characters of ref-A accordance .with my invention. Fig. 2 is a horizontal' Section taken in dotted-line 2 2 of Fig. 1. ig. 3 isan elevation of the carbureter. Fig. 4 isa sectional elevation through a carbureter illustra-ting another type of the adjustable air Valve. Fig. 5 is a vertical section through a form of carbureter adapted to be supplied with gaseous fuel.

5 designatesl the casing of my improved carbureter, the same being of any suitable form and dimensions. As shown by Fig. 1 of the drawings,'the casing is provided with a partition, 6, and with a seat portion, 7, said partition.6` and the portion 7 making provision for the accommodation of the two air valves, 8, 9. The casing is divided internally by the partition and the valves into three chambers, 10, 11, and 12, the first Elric plane of the f of which, 10, constitutes an air inlet chamber, the second, 11, a suction chamber in which a partial vacuum is created by the operation ofthe two air valves and by the suction draft from the engine, while the third chamber, 12, is a carbureting or mixing chamber to which the air and fuel are admitted in a way to be thoroughly com mingled therein for producing the combustible mixture.

The casing' is provided at a suitable point,

asin one side thereof, with an opening',` 13, which forms'an air inlet to the chamber 10, 'andthe lower end of the casing is closed by a suitable head, 14, which is shown as having a threaded-connection with the casing and as closing the bottom portion of the chamber 10.

The partition 6 is formed with an air opening, 15, that is spanned by a spider having a guide tube, 17, in which is arranged to play the stem, 18, ofthe air valve, 8. rThe upper side or face of the partition, 6, is finished to afford a seat for the valve 8, and said valve may be of the usual or any preferred construction. This valve is placed under tensionv by any suitable form of retracting device, but I prefer touse a retractor which may be adjusted to vary the tension on the valve, the latter being always exposed to atmospheric pressure because air is free to enter the chamber 10 and to act against the lower side kof the valve. As shown by the drawings, the stem 18, of the lower air valve 8 is extended through the air chamber, 10, and prolonged through af. guide nipple, 19, that is made integral with the lower' head, 14, of the casing. The pro` truding end of the valve stem is threaded for a part of its length, as at 20, and on itis screwed a nut, 21. A coiled spring,v22, is fitted loosely around the lower part of the valve stem, to findv a seat on the nut, 21, and to normally depress the stem and the valve for the latter to occupy the seat on the partition 6. A Shiftable'collar, 23, is fitted loosely on the protruding part of the valve stem and it rests or presses on the upper partA of the coiled spring, 22, and by forcing this` shiftable collar downwardly more or less, the tension of the spring and its action on the valve, may be varied. As one means for adjusting the collar, I employ a lever, 24, which is fulcrumed at a point in termediate of its length ona hanger, 25, depending from the head, 14, of the casing, and this lever is forked or -bifurcated at one end, said forked end of the lever fitting loosely on the valve stem and engaging with the shiftable collar. To the other end of the lever is pivoted the lower part of an upwardly extending link, 26, the upper end of which is pivoted to the head portion, ofan adjusting lever, 28. This lever is pivoted by a bolt, which passes through the head portionl of` the lever and av bracket-lug, 30, which is fast with the casing, 5 on'one side thereof. The lever is adapted to be held 1n an adjusted position by a suitable clamping device, such as the screw, 31, which is threaded in the bracket-.lug and passes through a slot, 32, that is provided in the head portion, 27, .of the lever concentric with the fulcrum, 29, thereof. lt is evident that the clamping screw can be releasedand the lever shifted in one direction in order to move thelever 24 and cause its forked end to press the shiftable collar, 23, toward the nut, 21, thereby compressing the spring and increasing the tension on the valve, 8, after which the screw 31 may be tightened for the purposejofv holdingthe valve under tension. The lever, 28, may, however, be moved in the opposite direction, Aand clamped in position, for the purpose' of relaxing the pressure of the spring and decreasing the tension of the valve, 8, but under all circumstances this valve is held under more or less tension for the purpose of making it operate at a different period from or dissimultaneously with the other air valve, 9, whereby the suction draft from theI engine is caused 'to exhaust the air from the chamber 11 in aV way to create a partial vacuum therein.

The air valve, 9, is shown in the form of 'a hollow-,cylindrical shell, open at its lower part, and closed at the upper part by. an imperforate head. This air valve is fitted snugly in the seat portion, 7, of the casing to normally occupya lowered closed position wherein its head is substantially flushwith a shoulder, 33, of the cas1ng,vwhereby the,

valve, 9, cuts off communication btweenth'e iso- CII

ber, 12, of the casing. This hollow air valve is of sufficient weight to drop by gravity to lowered to its seated position, but when the valve, 9, is raised by the suction draft through the casing` the ports of said valve are exposed more or lessabove the shoulder, 33 for the purpose ofestablishing communication between the chambers, 1l and 12, and thus permit the air to be exhausted from the chamber, 11, more or less'and to create a partial vacuum in said chamber before the spring-tensioned valve, 8, is opened by the continued application of the suction draft on the valve, 8.

In the embodiment of Ithe invention shown by Figs. 1 to 3`inclusive ofthe drawings, I have shown one embodiment of means for supplying a liquid fuel, such as gasolene, to the mixing chamber 12 at apoint above the air inlet to said carbureting or mixing chamber, and this fuel inlet is normally closed by a peculiar form of fuel valve which is con'- trollable by the operation of the air valve, 9, and is adapted to regulate the volume of fuel supplied to the chamber, 12, in proportion to the quantity of air admitted to said chamber, for the purpose of securing a mixture of uniform grade or quality under all conditions of speed or load of the engine.

A fuel supply pipe, r34k, is attached or coupled in a suitable way to the closed upper part of the casing which envelops the mixing chamber, 12, and with this pipe communicates a valve-tube, 35, the latter extending into the chamber l2. The upper part of this valve tube is conical in form While its' lower part is cylindrical to furnish a guide for the stem of a valve, 36. part of the valve-tube isl provided with av plurality of ports, 37, .which are shown as opening into the chamber, 12, and the conical or tapering fuel valve, 36, is ground into the valve tube for the purpose of making a tight fit or joint therewith, so as to effectually cut oil" the passage of liquid fuel when the valve is seated. Said valve is provided with a cylindrical stem, 38, which fits snugly in the guide portion, 39, of the valve-tube sol as to furnish a means for guidingthe fuel valve to movement in a rectangular path. The stem of the fuel valve is prolonged downwardly through and beyond the guide portion of the valve tube, and on this extended part of the stem is fitted a coiled spring, 40, the upper end of which is seated against the lower end of the valve-tube The conical A while the other end of the spring acts against a nut or collar, 41,.fixed to the lower extremity of the valve-stem.

v The lower end of the fuel-valve stem 38 terminates at a4 point just 'above the head of the air valve, 9, and thus the fuel valve has a coperative relation to the air valve to be actuated or controlled thereby when the said air valve is opened, although the fuel valve is seated quickly by thev action of its spring when the air valve is lowered by gravity to its seat. On the initial upward movement of the air valve, 9, it has a limited travel, for the head thereof to lift above the shoulder 33 and expose the ports in said valve before engaging with the stem of the fuelvalve; but on the continued ascent of the air valve, the fuel valve moves therewith, so that on the inrush of air into the mixing chamber, 12, the fuel is admitted through the ports, 37, into the valve tube, 35. The conical form of the fuel valve is advantageous in regulating the quantity of fuel admitted by the ports, 37, because the fuel valve has a movement or travel proportionately to the movement of the air valve, and

.this regulation of the fuel supply is also secured by the suction due to the maintenance of a partial vacuum in the chamber, 11, by the operation of the air valve, 9, and the spring tensioned valve, 8, as will hereinafter appear. p

Although I have shown the carbureter of Figs. l and 2 as having a hollow valve open at its lower` end and closedfat its upper end, I do not desire to limit myself to this particular kind of valve in connection with a character may be used in lieu of the hollow valve in a carbureter of the suction type just described; but when the carbureter is adapted to be supplied with liquid fuel under gravity pressure, I may use the adjustable air valve shown by 'Figs l, 2 and l of the drawings, whereby the volume of air admitted at each opening movement of the valve may be regulated to change the quality or grade of the combustible mixture. In Figs. 1 and 2, this adjustable air valve is shown as consisting of companion members, 9,9, each open at the lower end and closed at the upper end, said members being concentric one with the other and fitted together for one member to have a rotative movement with respect to the other, although the two members are adapted to travel or play as one part. iThe members of the valve are pivoted by a pin or bolt, 42,- and the respective members are provided with ports, 48, L14, of corresponding sh ape and area, said members being adjustable to vary the effective area of the air inlet afforded by said valve, The valve members may be adj-usted for the-ports thereof to register and produce an air inlet of maximum area, but one of the members may be adjusted relatively to the other to shift the ports therein more or less out of alinement with the ports of the' other member, and thereby reduce the area of the air inlet of the air valve, whereby on the lift of the valve the quantity of air admitted to the mixing chamber is reduced.

The rotative adjustment of one valve member relative to the other maybe eected Without stopping the carbureter by the devices shoWn, the same consisting of a short shaft, L15, journaled in a suitable bearing, 16, of the casing. The valve member, 9, has a narrow guide slot, 47, while the other valve member, 9a, has a comparativelywide slot, L18, in which is arranged to Work 'a crank or eccentric, 49, on the inner end p0rtion of the shaft, 45. To the outer end of this shaft is secured the enlarged end portion, 50, of an adjusting lever 51, said head portion of the lever having an arcuate slot 52, through which vpasses a binding screw, 53, that is threaded into the casing, 5, and is arranged to act against the lever for clamping it in an adjusted position. The lever and the shaft. are normally held sta* tionary, While the compound valve is free to have. a vertically slidable movement with respect to the arbor, but if it is desired to vary the area ofthe air inlet through the slidable valve, it is only necessary to release the binding screw and shift the lever in a certain direction, thereby rocking the shaft 115 and making the crank or eccentric '-19 act on the valve member 9a to turn the same With respect to the' companion'member 9,

thusbringing the ports in the two members more or less out of registration'.

The casing 5 of the carbureter has a suction connection for the engine, said connection having communication With the mixing chamber 12.

In operation, assuming that the lever 28 lis adj usted to relax the tension of the spring,

22, the vacuum maintaining valve 8 is practically 'free from restraint or tension, hence this valve 8 and the valve 9 Will work practically simultaneously on a suction draft from the engine through the suction connection 5ft and the chambers, 12, 11, the upward opening movement of the valve 9 operating' to unseat the fuel valve. This operation of thel valves, 8, 9, as just recited does not produce a partial vacuum in` the chamber 11, and it is not intended that the valve 8 shall be left free to open simultaneously with the valve 9. 0n the contrary, however, the lever 28 should be adjusted to compress the spring 22 and make it place the valve 8 under tension, thus preventing -the latter from opening simultaneously With the valve 9 and giving to the valve 8 an independent play or travel with respect to said valve 9, although both valves'are intended 'for operation by the suction draft of the engine. lVith the valve 8 under tension, the valve 9 free to lift by the suction draft, the fuelv free to flow through the pipe, 34, on the opening of the valve, 36, no matter whether the fuel is under head pressure or not, a suction draft from the engine'through the chamber 12 lifts the valve v9 Which in turn opens the fuel valve, 36, but as the opening movement of the spring-tensioned valve 8 is opposed by the spring or retractor, ,this valve (8) does not at once respond to the action of the suction draft, Whereby the suction creates a partial vacuum in the chamber 11 and in the mixing chamber 12, Which vacuum is available in drawing in a supply of fuel through the open fuel valve, 86, such supply of fuel being proportioned to the strength of the suction draft or the vacuum, 4and the fuel being drawn in by the suction irrespective of the existence of a head or gravity pressure of the fuel, as in cases Where the gravity of the fuel-head is not available owing to the changes in the position of the supply tank When the engine is used on a marine vessel or on a motordriven vehicle. With the air and fuel valves, 9, 36, opened, and the maintenance of a partial vacuum in the chamber 11, a continued application of the suction draft from the engine opens the valve 8 to admit air from the chamber 10 in to the chamber 11, and thus reduce the vacuum existing in the latter, whereupon the air rushes through the open valve 9 into the chamber 12 for admixture with the fuel and produces .the combustible mixture.

By increasing the tension ofthe spring 22, theopening movement 0f the valve 8 may be resisted increasingly to maintain anydesired state of vacuum, Within certain limits, With- -in the chamber 11, and this construction affords means by which the vacuum in the chamber 11 may `be utilized to regulate the quantity of fuel'that is induced to enter the mixing chamber owing to the existence of the vacuum, becausey the greater or stronger the vacuum maintained in said chamber 11 the more fuel that will be induced to enter the mixing chamber.

Immediately on the cessation of the suctionjfrom thev engine, the valves 8, 36, are seated by their springs, and the valve 9 returns by gravity to its seat, hence the carbureter is closedv against the admission of air t0 thehamber 11' and of air and fuelv to the chamber 12. Y f

I do not desire, however, to confine myself to the use of a regulating air valve wherein 'isl mama? the two parts are adapted for simultaneous movement, because the same result (air regulation) is attainable by the construction shown by Fig. 4. 1n this form of construction, the air valve, 55, consists of a hollow shell, open at the bottom and closed at the top, said valve having air ports, 56. The other part, 57, of the valve is stationary, being made fast to or integral with the shoulder 33a of the casing. This stationary valve member` 57 rises a suitable distance from the casing shoulder into the mixing chamber l2, so as to extend well above the position assumed by the air valvel when seated, and said valve member 57 is furnished'with a plurality of air ports, 58, which occupy such positions relative to the ports 56 of the movable valve member as to register therewith when the valve 55 is raised by the suction draft. Said valve 55 has a vertical slot, 58a, in which is arranged to play the crank on the rock shaft, 59, that is adapted to be manipulated by the lever 60, thus providing means for giving a rotative adjustment to the valve 55 and for bringing the ports 56 more-or less into registration with the ports 58 of the member 57 when the valve 55 is lifted by the suction draft.

' In Fig. 5 of the drawings I have shown a form of carbureter especially designed for use on a stationary class of internal com-4 bustion engines which are supplied with gaseous fuel from a city main. Under some conditions of supply from this source, it is found that at times the main is supplied with a head of gas under full gage pressure, while at other times the pressure drops to such a pointthat there is no appreciable gage pressure in the main, although there is a supply of gas available for utilization by a carbureter or mixer under one condition, namely, that the gas will be induced to How into the carbureter as by establishing and maintaining a vacuum, as contemplated by thisinvention. In View of the variation, or

the non-existence, of the gage pressure in the city main, a serious problem presents itself in the regulation of a carbureter for ythis class of work, in order' to make it responslve to the various fconditions of gasv supply and to insure the production of a combustible vapor of a standard grade or quality suitable for use in.an explosive engine. It is found, however, that a mixer or carbureter acting on the partial vacuum principle to induce the inflow of gaswhen no gage pressure. is indicated, and to regulate the volume of air supplied by an adjustable air valve as contemplated by this i-nvention, meets the practical requirements under the varying conditions.

When the gas in the main is under gage pressure, the admission thereof by opening the fuel valve in harmony with the suction-lifted air valve allows such a volume of gas to pass into the mixing chamber in proportion to the air admitted by the air valve as to result in a combustible mixture which is too rich in carbon to be utilized to the best advantage in the engine; and under such conditions of gas supply, it is necessary toadjust the air valve in a way to increase the volume of air supplied to the mixing chamber in proportion to the gas until a mixture of the desired grade or quality is secured. As shown, the casing of the carbureter consists of three parts, 60, 61, 62, the same being separably coupled one kto the other, and the end sections, 61, 62, being provided with removable heads, 64, each having a guide nipple, 65. The lower member, 61, of the casing is provided with a valve seat, 66, adapted to accommodate the vacuum-maintaining valve, 67, the stem, 68, of which passes through the guidenipple, 65, of the lower head. This valve stem is equipped at its lower end with a nut, 69, and with the coiled spring, 70, the upper end of which is engaged by the shiftable collar, 71, the latter being pressed into engagement with the coiled spring by the forked end of a lever 72. Said lever is fu'lcrumed on the hanger, 7 3, and to its otherwise free end is pivoted the link, 74, the other end of lwhich is pivoted to the head, 75, of an adjusting lever, 76, the latter being clamped in position by the screw, 77, all substantially as heretofore described in connection with the vacuum-maintaining valve shown by Figs. 1 to 3 inclusive," whereby provision is made for placingthe valve, 67, under variable tension.. The lower member, 61, of the casing provides an air chamber, 78, which is furnished with a normally n -is free to enter the chamber and act against the under side of the valve, 67.

The upper member, 62, of the casing affords a gas-supply chamber, 80, which is provided with a suitable gas inlet, 81. In the bottom Iof this member 62 is provided a valve seat, 82, and from this bottomk of said member depends a perforated cage, 83, the latter constituting a rose or spreader for supplying gas in thin streams to a mixing chamber, 84, on the opening of a gas'valve, 85. The cage or rose 83 is shown as having perforationsf in its bottom and in the surrounding wall, and frm the bottom of the cage risesv a guide tube, 86, in which is arranged to play the stem, 87, of the gas valve, 85, said valve stem extending through the guide tube, and projecting below the. botto its seat by the pressure or tension of a spring, 88, which acts'on the upper side of the valve. This spring envelops an adjustiso ing Spindle or pin, 89, which has threaded engagement with the nipple, 65 on the upper head, 64, of the casing; said spindlebemg provided with a collar 91, against which is seated the upper end of the gas-valve spring, 88. Thelower end of the spindle 1s loosely received ,in a hollow or chambered' upperwhen it is desired to change the tension of the spring, 88.

Within a seat portion, 90', of the middle member of the casing is fitted an adjustable air valve, consisting of two parts or members- 93, 94, said air valve Vbeing constructed as shown by Fig. lor by Fig. 3,' as preferred. For the sake of convenience, however, I have shown said adjustable air valve as consisting of two movable members, 93, 94, each open at the lower end and closed at -the upper end; said members' being pivoted together at 95 and each being provided with ports, 96. The member, 93, is provided in one side with a narrow groove, 97, and the member 94 is shown asy having a wider groove 98, the latter receiving the crank, 99, on theinner end of a short shaft,

100, which is journaled in the'v member 60 of the casing. To the outer end of this shaft is secured thel adjusting lever, 101, that may be held in adjusted .positions by a suitable clamping screw, 102, all substantially as hereinbefore described. The described -construction provides means for imparting a rotative adjustment to the members Vof the air valve in a way to vary the area of the air inlet, and this adjustment may be performedeasily and quicklyand without arresting the operation of the air valve and thecarbureter.

^ The head. of the slidable air valve, and i'he stem 87 of the gas valve, are arranged close to one another so as to have a coperative relation, and on .the upward movement of the air-Valve, its head engages with the foot of the gas-valve stem, sovthat the gas valve, 85, will be unseated orlifted on the ascent of the air valve, whereby the two 'valves operate in unison.

Under normal conditions all the valves are seated, the adjustable air valve serving to divide the middle member 60 of the casing into a partial vacuum chamber, 103, and the mixing chamber 84, hereinbefore mentioned. When the gas is supplied under gage pressure in the main to the chamber,

80, of the carbureter, there should be a very light tension exerted* by the spring, 70, on the valve, 67, thus permitting this valve to openfreely with the adjustable air valve by a suctiondraft'through the carbureter from the engine. This operation -does not vpro- 'vide for the maintenance of a vacuum in the vunder varying gas pressures.

chamber, nor is. it necessary to do so, because the gas is supplied under pressure; but this fact makesit necessary to regulate the volume of air admitted by the valve, 93, 94. It is evident that the valve may be adjustedv by shifting the position of the lever,

v101, which in turn imparts a rotative move- .grade or quality, and this is advantageous because the volume ofgas supplied by the valve .85 may vary with the gage pressure, hence -the carbureter is controllable to secure a standard grade or quality of mixture however, that the gas supply in the main may drop to a point where there is no gage' pressure,hence` thel gas will not flow into the chamber 84 when the valve 85 is opened, but to overcome this objection, the lever 76 may be moved to make thespring, 7 0, exert tension on the valve, 67, whereby the opening movement of' the valve 67 is'opposed whereas the air valve is free to open by the suction draft. yNow, a suction draft from the engine lifts lthe air valve which in turn unseats the fuel valve, 85, thereby establishing and maintaining a partial vacuum in the chamber, 103, which is available in inducing the inflow of a quantity of gas proportional to the air for admixture therewith to secure the combustible mixture. Of course, the suction draft will open the valve, 67, after the establishment of the vacuum in the chamber, 103, and the drawing in of the supply of gas to the chamber 84, so that the air in necessary volume is admitted to the mixer. The volume of the air admitted bythe valve, 67, and the quantity of gas drawn in by the establishment of vacuum in the chamber 103, may be controlled by placing morev or less tension on the valve, 67, as will be understood.

My improved mixer or carbureter constructed as shown by Fig. 5, or in an equivalent manner, for. taking gas from a city main is automatic in regulating the admission of the requisite volume of gas and air to secure astandard grade or quality of combustible mixture when. the gas pressure luctuates within vcertain limits, although when the gage pressure is at a comparatively high point it maybe necessary to regulate the adjustable air" valve to increase the volume of air in proportion to the gas which enters in greater volume owing to the pressure, and on the diminution of supply below gage pressure it is necessary .to-interposta- -It is found,l

the tension of the spring on the valve 67, so as to establish and maintain a partial vacuum in the chamber 103 for inducing the inflow of gas.

As just stated, an advantageous feature of my mixer is its capacity for self regulation when used to secure a supply of gas from a main, or its equivalent, the pressure in which may vary within limits not fally ing below gage pressure. Under such con* ditions, practically no tension is exerted on the valve, G7, and the two-part air valve 93, 94, or its equivalent, is exposed to atmospheric pressure, while the gas valve, 85, is subjected to pressure from the source of gas supply, whereby the air valve and the gas valve are balanced one against the other. A slight upward travel of the balanced air valve due to the suction draft from the engine is resisted by the pressure of gas on the gas valve and by the tension of the spring, 88, so that on the prevalence of high gas pressure in the source of supply, the gas valve 85 is not opened fully .or widely by the .movement of the air valve, and the required volumes of air andv gas are admitted to produce the combustible mixture, the gas and the air rushing at a higher velocity through the respective inlets. A decrease within a certain limit in the pressure of gas in the source of supply offers less resistance to the movement of the gas and air valves, hence the gas valve will open wider when lifted by the air valve and the required volume of gas, under the decreased pressure, is admitted to the chamber 8i in proportion to the volume of air ad* mitted by the air valve under the increased travel imparted thereto by the suction draft.

Special stress is laid on the provision of suction operated means in a mixer or carbui-eter for establishing and maintaining therein a partial vacuum for inducing the inflow of fuel for admixture With air, because herein lies the broad feature of my invention.

Importance is also attached to the provision of means by which the strength or' degree of partial vacuum is controllable at will in the mixer or carbureter, said end being attained by interposing more or less resistance to the opening movement of the vuomini-maintaining valve. rlfhis is an advantageous feature of my device because on it rests the control of the volume of fuel which is admitted at cach opening movement of the air and fuel valves, whereby provision is made for regulating automatically the supply7 of fuel in volumes proportionate to the quantity'of air to automatically produce a combustible mixture uniform in grade or quality under varying speeds or loads of the engine.

These broad features of the invention may be secured in a mixer or carbureter by the employment of different combinations of devices, examples of which havev already been given, and it is to be understood, therefore, that 1 do not strictly confine myself to the specific construction and arrangement of devices shown by the drawings. Nor do I in every instance desire to limit myself to the use of valves of the specific class herein disclosed, because valves of other types, such as swinging or rocking valves, may be used in lieu of sliding valves to carry out the principles of the invention. Furthermore, changes in the form, minor details of construction, size and proportion of parts may be made Without departing. from the spirit or sacrificing the advantages of my invention. 'I therefore reserve the right to make such alterations as fairly fall within the spirit of the invention as defined by the annexed claims.

What I claim as new, and desire to secure by Letters Patent is z* l. A carbureter having a chamber, an air valve, a fuel valve controllable by said air valve, and means under tension and operating independently of the aforesaid valves for maintaining in said chamber a 'partial vacuum'k equal to that established by a. suction draft through said chamber, whereby such vacuum draws fuel from a fuel inlet valve into said chamber.

2. A carbureter having a chamber, a fuel inlet thereto, and a plurality of independent suction-operated devices, the one of said devices which primarily admits air to sa-id chamber being under tension, the aforesaid devices operating to maintain in the chamber a partial vacuum equal toV that established by a suction draft through said chamber, whereby such vacuum draws fuel from the fuel inlet into said chamber.

3. A carbureter having a chamber, a fuel inlet to said chamber, air and fuel valves, and suction-operated means under tension and independent of the aforesaid valves for maintaining in the chamber a partial vacuum equal to that established by a suction draft through said chamber, whereby such vacuum draws fuel from the inlet into said chamber. A

4. A carbureter having'a valved chamber, a fuel inlet to said chamber, a plurality `of air valves adapted to be unseatcd successively by a suction draft through the chamber, a tension device cooperating with the valve by which air is admitted initially 'te' said chamber, and a fuelvalve controllable by one of said air valves, theconstruction and arrangement being such that a partial vacuum is maintained in the chamber equal to that established by it" suction draft through said chamber, whereby such vacuum draws 'fuel through the fuel inlet into* the chamber;

5. A carbureter having a carbureting chamber, an air valve, a fuel valve for admitting fuel to said chamber, and a vacuummaintaining valve operating independentlyof the air valve and subsequent to the opening movement of the latter, whereby a. partial vacuum is maintained in the carbureting chamber equal to that established by a suction draft therethrough.

6. A carbureter having carbureting and vacuum chambers, air and fuel valves operatively related tothe carburetiiig 'chamf ber, an independent vacuum-maintaining valve for the vacuum chamber, and a tension device for said last-mentioned valve, whereby the valves .operate to maintain in the vacuum chamber a partial vacuum substaiitially equal to that established by a suction draft through said chamber.

7. A carbureter having a chamber, an air valve,- a fuel valveto supply fuel to said chamber, a vacuum-maintaining valve independent of the lair valve, and arranged to be operated by a suction draft for maintaining a partial vacuum in said chamber equal to that established by ay suction draft therethrough, and a tension device for the vacuum-inaintaining valve. 8. A carbureter having air and fuel valves, a vvacuum-maintaining valve Aindependent of the aforesaid valves, and means opposing the opening movement of the lastmentioned valve and insuring thereto'operation `subsequent to the air valve.

9. A oarbui'eter having a chamber, a fuelsupply therefor, two air valves arrangedfor independent operation under a suction draft,

and a variable tension device for one of said valves.

10. A carburetei having a chamber, a fuel supply therefor, two air valves arranged for independent operation under a suction draft, a tension device for one of said valves, and means for effecting a variation in the resistance of the tension device.

11. A earbureter having a chamber, av fuel supply therefor, two air valves larranged for independent operation by asuetion draft, a tension device for one of said valves, a lever, and means actuated the lever for varying the resistance of the tension device. v

12. A carburcterhaviug carbureting and vacuum chambers, a fuel supply for they carburetiiig chamber, two valves coperat` ing with the vacuum chamber` and' one lof said valves being free to open by a suction draft, and a tension device opposing the movement of the other valve.

13. A carbureter having carbureting and vacuum chambers, a fuel valve for the cai'- bureting chamber, an air Valve between the tivo chambers and arranged to control theA fuel valve, another air valve for the vacuum chamber, and a tension devicefor thev last mentioned valve.

vacuum chambers, a variable air valve controllingthe communication between the chambers, suction operated means for establishing and maintaining a partial vacuum in ythe Vacuum'chamber, and a fuel valve for the carbureting chamber.

16. A carbureter having carbiireting and vacuum chambers, a fuel valve for the carbureting chamber, an' air valve between the two chambers, means for varying` at will. the area of the air inlet afforded by said valve, and'suction operated means for establishing a partial vacuum in the vacuum chamber.

17. A carbureter having carbureting and vacuum chambers, a valved fuel inlet tothe cai'bureting chamber, a valve between the chambers, a valve at the inlet to the vacuum chamber, and means controllable at will for interposing av variable resistance to the opening movement of the last'mentioned valve.

1S. A carbureter having a fuel'valvey subject to the vpressureof fuel in an available source of supply, an air valve arrangedto actuate the fuel valve and adapted to be itself operated by a suction draft, and means operatingl independently of the aforesaid valves for maintaining a partial vacuum equal to that Iestablished by a suction draft through a chamber, such vacuum being available in drawing fuel from said source of supply through the fuel valve.

19. A cai-bureter having a fuel valve, an air valve, suction-operated means acting independently of the aforesaid valves andv maintaining a partial vacuum equal to that established by a suction draft through a chamber, and means controllable at will for varying the extent lor strength of said partial vacuum.

20. .In a carbureter, a chamber, means connecting with said chamberwhereby a suction draft from an engine establishes a partial vacuum in said chamber, means for sup-l plying a combustible to said chai'iiber, and a plurality of air admission valves positioned in alinementfwjith each other and adapted to control the `flow of air-into andfthrough said chamber, said plurality of air admission valves kbeing positioned foi' operation successively and at each period a suction draft is established within said chamber.

21. @K carbureter comprising a casing having a plurality of chambers, means whereby one of said chambers is adapted 'to be placed in substantially direct communication with an eiigine,^a suction operated ,valve intermeiio diate said chambers, a tension-control1ed of my invention, I have hereunto signed my valve'controlling the admission of air to the name in the presence of two subscribing other of said chambers, and means for sup- Witnesses.

plying fuel to that chamber Which is adapt- EDWIN vIT ABERNE'IHY. 5 ed to be placed in substantially direct com- Witnesses munication with the engine. ALONZO C. FARNHAM,

In testimony that I claim the foregoing as GIFFoRD LE VELSAM. 

